How to increase contrast / reduce haze?

[allklier]

Living in WA there are many exciting mountain ranges to shoot. But I find that

my pictures turn out with too much haze. What is the correct technique for a

shot like this to come out well?

 

<p>Here's a shot I took of Mt. Hood from Portland: <a

href="http://www.photo.net/photo/5547348">original</a>

 

<p>I later post-processed the picture in software and increased the contrast,

which helped it a bit, but still didn't really bring it out: <a

href="http://www.photo.net/photo/5547347">adjusted

contrast</a>. Plus, ideally I'd like to take the shot so that post processing

is unnecessary or minimal.

 

<p>The picture was taken with a Canon EOS 400D, 70-200mm L lens at 200mm, with

circ polarizing filter, ISO 400, F/18, 1/160, shutter priority and 0.33

exposure comp.

[michaelging]

Photography has always been a craft of compromise, and digital is no exception. You have to use all the tools in the toolbox to get the image you want at the last process. Photoshop or post processing is just one of those tools. I am wondering why you shot the photo at F-18, and not a faster and sharper f-stop such as F8.

[allklier]

Good points. My logic on these points was:

 

Having the software is a good tool to save a shot, but aspiring to get it right in the camera encourages me to improve technique and avoid getting sloppy because I have the software to back me up. So where the tool can enhance the range of the camera beyond its limitation, I think it's a fine choice to use the software.

 

Regarding the F/18 - from a creative exposure point of view I considered it a don't care on aperture, and set the shutter priority to allow me to hand-hold the camera given the heavy lens. But that is a fair question: does the sharpness / depth of field really come into question on a subject that is literally 100 miles distant?

[michaelging]

The DOF on a object at infinity is a non issue. That is why I would have shot using the sharpest part of the lens , which would have also given you a faster shutter speed.Haze in a photo can be used to your advantage to show depth.My first point is that you use all the tools at your command to get the photo you are looking for as a end product. To think that you will get all the variables , of color,contrast,sharpness,texture in the photo at the moment of exposure is asking more than the photographic process can give you.If you are lookng for maximum contrast in a photo, shooting at the slowest ASA will help,noise in any photo is usually found in the blue channel and most of your photo is in this color.I agree that you want to start out with the best file or neg you can , and then do the finishing touches in PS. If you shoot in the RAW format you will have all the information that the camera had at the moment of exposure.

[elf]

in this case, as in many in humid locations you really can't expect photography to do a

whole lot better. Basically if you're stuck there on that kind of day, that's the luck of the

draw.

 

But if you can arrange to draw a better day, then you will get a better image.

 

that haze is not a function of your tools, or your choices with your tools. It's a function of

the crappy photographic situation.

 

I will say I would have underexposed under that circumstance, however. And maybe a trip

to channels could clear up a little of the junk.

[elf]

I doubt this is really any improvment, since the color looks pretty awful to me.

 

But pulling the brightness down with curves and tweaking the color balance in

Image>Adjustments>Channels and then seriously futzing with the levels produced a more

contrasty image.<div></div>

[w.smith]

UV filter?

[Ed_Ingold]

Haze of this sort is due to scattering from gases and sub-micron dust particles, which is often polarized (much as the sky is polarized due to scattering). Using a polarizing filter can significantly penetrate the haze and increase contrast. A UV filter may help, but usually not as well. It would be interesting to test the effect of a B+W 486 "hot mirror" filter, which is tuned to eliminate both UV and IR.

 

Beyond that, you can improve the contrast in post processing in many ways. One technique, which is non-destructive, is to create a duplicate layer and use "Multiply" or "Soft Light" blending.

[mike_earussi1]

Jan, why would you own a nice expensive L lens and then purposely shoot it at f18, an aperture guaranteed to lower the contrast and sharpness so much you might as well be using a coke bottle instead of a lens?

[allklier]

Thanks for everyone's thoughtful replies.

 

Emily - your version doesn't overcome the haze, but by making it more sunset like looking it does make the haze less noticeable as the added red tones balance out the mostly blue haze.

 

Edward - I will try it with different filters next time and compare. For this shot I used a polarizing filter. Is it possible, and a valid technique, to take the shot multiple times with different filters and then overlay them?

 

Mike - I didn't realize that the f-stop made such a big difference re: sharpness and contrast in this case. On my next opportunity I will take the shot with a range of f-stops so that I can learn the difference it has. Thanks to you and Michael to pointing this out.

[bill_proud]

All,

 

Don't suppose I'll win any friends but had to jump in here.

 

First, Jan, the rule of thumb is don't handhold the camera when the shutter speed is less

than the focal length. You are shooting a 200mm lens at 1/160 of a second. Using the rule

your shutter speed should be at least 1/200 or faster, maybe 1/400 sec. depending on

how steady your hands are. For this reason I would have opened up to f/16 or 11, which

would give you the higher shutter speed needed for handholding.

 

Second, I'm not seeing much of a polarising effect at all. If this image is polarized I can

only imagine how murky it must have been.

 

Lastly, you are shooting expensive L glass, the effects of diffraction at f/18 versus f/8 is

very minimal with that lens.

 

There may instances where the tradeoff between depth of field and diffraction effects are

critical but in most cases get depth of field before worrying about diffraction, especially in

nature, landscapes and such.

 

good luck,

 

www.billproudphotography.com

[mike_earussi1]

Bill, defraction limitation is a universal law of physics and cannot be improved upon by lens design. Admittidly I was exaggerating just a bit with my earlier comment, but the reason one buys a high quality lens is so you can shoot it wider apertures to minimize the negative effects of defraction, which are lower resolution and contrast. The 70-200 f4 L peaks out around f5.6 in overall optical quality. The only reason to shoot it at a lower aperture is to increase DOF or to cut down on light. By f18 I doubt you'd be able to tell much difference between an expensive lens and one much cheaper.

 

Jan, to maximize contrast:

 

1. Shoot at the optimum aperture of the lens.

 

2. Shoot at the lowest ISO possible (higher ISO's just add noise and lower both resolution and contrast).

 

3. Use a tripod with mirror up and cable release or self-timer to maximize sharpness, as a fuzzy image lowers contrast.

 

4. Use a lens hood to minimize glare.

 

5. And use a polarizer--which you did.

 

Hope this helps. Mike

[mike_earussi1]

Bill, defraction limitation is a universal law of physics and cannot be improved upon by lens design. Admittidly I was exaggerating just a bit with my earlier comment, but the reason one buys a high quality lens is so you can shoot it wider apertures to minimize the negative effects of defraction, which are lower resolution and contrast. The 70-200 f4 L peaks out around f5.6 in overall optical quality. The only reason to shoot it at a lower aperture is to increase DOF or to cut down on light. By f18 I doubt you'd be able to tell much difference between an expensive lens and one much cheaper.

 

Jan, to maximize contrast:

 

1. Shoot at the optimum aperture of the lens.

 

2. Shoot at the lowest ISO possible (higher ISO's just add noise and lower both resolution and contrast).

 

3. Use a tripod with mirror up and cable release or self-timer to maximize sharpness, as a fuzzy image lowers contrast.

 

4. Use a lens hood to minimize glare.

 

5. And use a polarizer--which you did.

 

Hope this helps.

 

Mike

[sheldonnalos]

The correct answer is to drive to Sandy or Hood River and take your picture again. Or, if you want to shoot from Portland, do it on the first clear day after a good rain, when the atmosphere is clear.

 

No technique or gear can overcome 30 miles of haze in the air.

[john_willard]

Hi Jan,

 

I had some fun with messing with your photo. As Sheldon implies, a less than perfect scene will make nothing more than a less than perfect picture. In your shot the helicopter obviously caught your attention and you were trying to do what you could given the moment. So what the heck, photography is supposed to be fun and you got yourself a fun shot.

As for what I did to the picture. I had three layers; Levels, Hue&Saturation, and Brightness/Contrast. Under Levels your histogram was bunched up to the left of center so I pulled the little arrow on the right almost to the middle. Hue&Saturation, haze shots are heavy in the cyans and blues so some desaturation and a little lightening of those two colors were used. Brightness/Contrast I bumped up the contrast quite a bit, but then the sky got blotchy. So with the B/C layer active I used the erase tool to remove that adjustment from the sky.

Is my result perfect? HAHAHAHA!! I know better than proclaim something like that. My result is just different. Some will like it and others won't.

Like I said, photography is fun and I just had some fun with a fun picture, thanks for the opportunity.<div></div>

[stp]

I think Sheldon said it best. Haze varies from day to day, and it often depends on which way

the wind is blowing (or not blowing). Get away from a metropolitan area, don't position a

metropolitan area upwind, don't shoot on a winter day with high pressure and no wind and in

the vicinity of a metropolitan area (i.e., air stagnation alerts), don't shoot during the summer

fire season, use a polarizer (and a tripod), and/or shoot in the morning when the haze is

generally lower. All of these will help. Telephotos "magnify" the effect of haze (they

generally peer through a greater amount of haze due to longer distances).

[frank uhlig]

The only sure answer is for humans to produce fewer small particles with their cars, engines, soot etc; less pollution would do it.

 

The better the lens, the clearer the intermediate soot and smog becomes. There is no way to filter it out optically, since these particles just hang in the air and are there physically, chemically. No tripod, film, glass or ps filter can help because what you see in the pic is really there between you and the mountains 20 miles away, just as a tree would obscure part of the scene: unfilterable; standard by-product of our own pollution.

 

Sorry. Some magic days, the wind can drive this smog away; after a rain it might have been washed into the gutters, maybe. You could try military x-ray vision cameras, maybe, but these cost millions.

[aaron_muderick]

Try converting the image to LAB and steepening the curve in the Lightness channel. Tweak the A+B channels indepedently to get the correct color balance. This is a great way to break through haze in post-processing.

 

Search online for more info on LAB and LAB touch-up techniques.

[bill_proud]

Mike,

 

Let me try another stab at this. I'm not arguing physics with you. Yes there will be

diffraction effects, especially at longer focal lengths and higher f/numbers,(smaller

apertures). Each photographer must decide where he/she is willing to sacrifice between

depth of field and diffraction to get the shot they want or need.

 

you can talk about theory all you want but we live in a real world. If you are trying to get

published, and many on this forum are, and not having success, perhaps shooting at the

optimal f/stop is costing you that success.

 

I have been published many times in the landscape arena and I'm just passing along

information, for free, about how I went about it. You can judge these results on my

website. If my info helps you, great.

 

For me, I will use the smallest aperture needed to get the depth of field necessary to sell

images.

 

And yeah, Jan, you probably should have come back on a better day as Sheldon said.

 

 

good luck,

[crabseye]

"The correct answer is to drive to Sandy or Hood River and take your picture again. Or, if you want to shoot from Portland, do it on the first clear day after a good rain, when the atmosphere is clear.

 

No technique or gear can overcome 30 miles of haze in the air."

 

I'm not exACTly sure it's the same on the Left coast, but shooting occasionally in the Blue Ridge mountains, infamous for their blue haze, the only hope of contrast and clarity is the weather. This may or may not be the first clear day after a good rain. It WILL be a day with winds from the North, with a high pressure system in place. Humidity will be low, haze will be low.

 

Watch the weather maps in your area for several weeks. Learn what weather features (high/low pressure systems), in what positions relative to yours, produce optimal shooting conditions.

 

If your high pressure dominated days are rare, be happy that those hazy days often give the most colorful sunsets ....

[matthew_newton]

If memory serves (and it does sometimes) I think the optimal f-stop to shot on where diffraction will begin to limit the COF in an image is about f/8 (I think like 7.8) on a full frame/35mm sensor/film. I don't remember what it is on an APS-c sized sensor, but I think it is closer to f/6.3-6.7 and the small digicam sensors it is something like f/2-f/2.8.

 

Of course just how much of an effect that diffraction is going to have is the question. Also as someone mentioned sometimes you NEED that depth of field to capture the image you are after. That is much more important then any negative effects diffusion will have on the picture. The diffusion is also not going to greatly reduce the image quality unless you are going overboard. (on a 35mm format) f/32 is going to be easily noticable next to an image taken at f/5.6, f/16 might be noticable if you do a 100% mag of a section of an image compared to f/5.6, I doubt you could see much of any difference even at large magnifications at f/11 or f/8.

 

My rule of thumb is shot at the widest aperature I can to get the depth of field I need. I do however try to keep the aperature at f/5.6-f/8 (f/4 with my faster lenses)...as most of the lenses I have are sharpest in that range and there is also a minimal effect of diffusion on the image.

 

A polarizer can help with haze shots, but it won't eliminate it. It has been beaten to death, but haze are actual particles in the air. you are basically just going to have to wait for pollution to cease (supposedly a person could see clearly for 100 miles to mountains when we first settled America 2 or 3 centuries ago...now we are lucky to see 30 or 40 miles on a clear day) or else wait for a particularly clear day for photography.

[matthew_newton]

I looked and found out my information wasn't quite correct on obtaining maximum resolution with a digital sensor. It was close though. Read down to near the bottom and it gives the f-stop and effective f-stop to receive maximum resolution on a given image sensor http://www.luminous-landscape.com/essays/Equivalent-Lenses.shtml

 

It is an extremely good and long article that brings up many things about diffraction.

[wieslaw1]

Jan - what is wrong with haze?<div></div>

[wieslaw1]

I just quickly scanned through some nonsenses above and have

to clarify.

 

First of all the stop range on you lens does not affect the contrast

of the film (there is no physical law responsible for this!), neither

it affects the sharpness in a way that you will ever notice it on

your print, and I assume you do not enlarge your pictures 30X, or

do you?

 

If you change f-stop you simply change the depth of field and the

amount of light coming into the camera, without applying

dubious philosophy as to the other effects!

 

 

 

Mike - question to you, a) what is defraction? Never heard about

it.

b) 'By f18 I doubt you'd be able to tell much difference between

an expensive lens and one much cheaper. ' You are very wrong!

(and it is f/18, not f18).

 

Next one: 'Each photographer must decide where he/she is

willing to sacrifice between depth of field and diffraction to get the

shot they want or need. '

 

No way! Dont you guys worry about diffraction.

Show me please a single shot of yours which demonstrates the

diffraction effect, as opposed to a photo which is diffraction-free.

 

PS. By the way, you dont like haze, use IR films

[somak_ray]

A lot of insightful answers here. I know that a mist filter works well when the aperture is small(large f numbers). Can haze be considered something like a mist filter? In that case a smaller aperture like f/18 will increase the haze's effect compared to f/8.Your comments are solicited.

Thanks